As the investigation into vanished Flight MH370 shifts to the pilots for any sign they would want to hijack the plane or commit suicide by crashing the jetliner, the investigation has cast a spotlight on the psychological oversight of pilots.

In the U.S. the Federal Aviation Administration (FAA) has a strict policy that requires all pilots flying commercial aircraft to have a first class medical certificate. Part of getting that certificate requires pilots to have a physical examination by an FAA-designated Aviation Medical Examiner, who also assesses the pilot’s psychological condition.

Pilots under 40 get the physical exam every year and those over 40 have to get the exam every six months.

Dr. Bob Worthington, a former US Army aviation psychologist and part of the FAA member safety team, said doctors would look for a host of conditions from drug addiction to schizophrenia and impulse control that could make a pilot unfit to fly.

“They’re looking for mental conditions that would render a pilot unable to safely perform or a condition that would interfere,” said Worthington.

However, the exam depends upon the pilots answering truthfully.

"An expectation is that the pilot is supposed to tell the truth," said Worthington. "The penalties for lying can be pretty severe and include losing your flying certificate."

The Malaysian Department of Civil Aviation requires all pilots to have a Class 1 Medical Examination that must be renewed every year for those under 40 and every six months for those over 40. According to the department website the exam includes ECG, general health, hearing and eyesight checks and says "certain other medical conditions" that may prevent a person from being a pilot.

Requests from the Department for further information about psychological testing were not immediately answered. The International Civil Aviation Organization (ICAO,) of which Malaysia is a member, suggests that pilots be screened for multiple psychological conditions and lists medications that should bar a person from flying.

A hijacking or pilot suicide is incredibly rare and so far there has been no evidence that either pilot of Flight MH370 wanted to commit suicide. A study by the FAA found that just eight of 2,758 fatal aviation accidents were the result of pilot suicide. Only one of the accidents involved the deaths of someone other than the pilot.
However, as the investigation continues experts say all aspects of the pilot’s private lives will likely be scrutinized for clues.

“If we had a dead pilot and an aircraft [down] we looked at his [literal] baggage like his medications,” said Allan Diehl, a former crash investigator for the FAA and National Transportation Safety Board. “You’re going to move to check out the human aspect. That would have happened the next morning.”